Compound action shears

ABSTRACT

Hedge shears having increased cutting efficiency and operator shock isolation are provided by this invention. Improved cutting efficiency is provided by a cam actuated force multiplier interconnection of the blades. Shock isolation is provided by the use of resilient means to limit the blade travel.

United States Patent La Pointe [451 Mar. 21, 1972 54] COMPOUND ACTION SHEARS 1,670,201 5/1928 McGary ..3o/271 x 122 603 1/1872 Hall ..30/238 I l l P [72] e M wmeste" Mass 2,227,531 1/1941 Cantrell.... ..30/238 x [73] Assignee: Parker Mfg. Company, Worcester, Mass. 2,384,822 9/1945 Drmic.... ..30/250 [22] Filed: Apr. 24 1970 3,324,549 6/1967 Sharp ..30/l93 X [21] Appl. No.: 31,488 Primary Examiner-Andrew R. Juhasz Assistant Examiner-Michael Koczo, Jr. 52 us. (:1 ..30/238, 81/416 Bbdge [51] Int. Cl. ..B25b 7/06, B26b 13/28 58 Field ofSearch ..30/271,254, 252, 191,192, ABSTRACT 30/193 239; 81/416 Hedge shears having increased cutting elficiency and operator shock isolation are provided by this invention. Improved [56] References Cited cutting efi'iciency is provided by a cam actuated force mul- UNITED STATES PATENTS tiplier interconnection of the blades. Shock isolation is provided by the use of resilient means to limit the blade travel. 884,281 4/1908 Linda] ..30/239 3,196,540 7/1965 Porsky ..30/254 5 Claims, 4 Drawing Figures PAIENTEDMAR21 I972 SHEET 1 BF 2 GABRIEL M. LAPO/NTE IN VE N TOR.

PATENTEDMARZI I972 3, 650.028

sum 2 [IF 2 FIG. 4

COMPOUND ACTION SHEARS BACKGROUND OF THE INVENTION This invention relates to hedge shears and, more particularly, to improvements in the structure of hedge shears resulting in increased efficiency, improved operation and longer life.

Hedge shears commonly available comprise a pair of crossed blade-handle members pivoted at a central point. Such constructions have many disadvantages. All of the wear takes place at the pivot point. There is no provision for the multiplication of the effort expended in the operation of such shears. There is no common provision to isolate the hands of the operator from the shock resulting from the final contact of the blades when the limit of their travel is reached. The blades of the prior art devices are also commonly of the blade and anvil variety and thus the beneficial results obtained from the use of a serrated blade cannot be enjoyed. The shears of the prior art are also frequently subject to jamming due to the nature of their construction which gives rise to frictional contact between the operating parts.

SUMMARY OF THE INVENTION The shears of the present invention overcome the disadvantages of the prior art. The blades of the shears of the present invention are interconnected in such a manner that the force applied in actuating the handles undergoes a mechanical multiplication upon encountering resistance to the cutting action of the blades. This is accomplished by the interconnection of the blades by a particular cam arrangement as will be described further in greater detail. The present invention eliminates the heretofore employed common pivot point, spreading the resultant wear and providing a longer effective life. Resilient stop means are provided to limit the travel of the blades of the shears thus effectively isolating the user from the shock normally encountered when the blades reach the limit of their travel. The multiplication of the force applied and the ability to use a serrated blade in the present construction permit a unique design which no longer requires frictional contact of the blades. This eliminates the consequent tendency of the shears to jam or otherwise be hard to operate. Cutting of small branches is made possible by the provision of an arcuate notch in one of the blades. These and other features of the present invention will become more apparent by consideration of the drawing and the following detailed description.

DESCRIPTION OF THE DRAWING The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawing, in which:

FIG. 1 is a top plan view of the shears of the present invention, showing the blades in closed position,

FIG. 2 is a side elevational view of the shears of FIG. 1,

FIG. 3 is a cross-sectional view of the shears of the present invention taken along the lines Ill-III of FIG. 1 and illustrating the handle stop members, and

FIG. 4 is an exploded view showing the relationship of certain of the elements of the shears of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawing, there is shown a compound action shears according to the present invention. The shears have a first blade and a second blade 11. Each blade has a forward or cutting portion 12,13 and a rear or base portion 14,15. As illustrated, the cutting portion 13 of the second blade 11 is preferably serrated. The cutting portions of both blades can be serrated, if desired. A first handle 16 is fixedly attached to the base portion 14 of the first blade 10 by means of a rivet 17. A second handle 18 is pivotally attached to the base portion of the second blade 11 by means of a rivet 19. The base portion 14 of the first blade 10 is provided with a stud 20. The

base portion 15 of the second blade 11 is provided with an elongated slot 21. This slot 21 is oriented in the base portion 15 of the second blade 11 so that the long axis 22 of the slot intersects the centerline 23 of the second blade 1 1 at an angle of about 1 1 in order that in operation the maximum severing effect of the combined action of the cutting portions 12,13 of the blades 10,11 can be achieved. The slot 21 of the base portion 15 of the second blade 11 receives the stud 20 of the base portion 14 of the first blade 10. To permit ease of action, a washer 24 can be provided on the stud 20 between the base portions 14,15 of the blades 10,11. The base portion 15 of the second blade 11 is also provided with an elongated recess 25 positioned forward of the slot 19. This recess 25 is inclined toward the rear of the base portion 15 of thesecond blade 11. A bolt 26 interconnects the first handle 16, the base portion 14 of the first blade 10 and the second handle 18. The recess 25 in the base portion 15 of the second blade 11 fits around the bolt 26. The bolt 26 is held in position by a nut 27. A washer 28 can be provided between the head of the bolt 26 and the second handle 18.

The first handle 16 and the second handle 17 are provided with grips 29. These grips 29 can be provided with eyelets 30, if desired, for hanging the shears. The travel of the blades 10,11 in operation is limited by a pair of stops 31 on the handles 16,17. These stops 31 have a resilient portion 32 to cushion the shock of impact. The stops 31 are fastened to the handles 16,17 by rivets 33 or the like.

To aid in cutting small branches, the second blade 1 1 can be provided with a sharpened arcuate nipper 34 which coacts with the cutting portion 12 of the first blade 10.

In operation, the shears are held by the grips 29. Opening the handles 16,18 away from each other permits movement of the blades 10,11 away from each other. The stud 20 of the base portion 14 of the first blade 10 travels in the slot 21 of the base portion 15 of the second blade 11. The recess 25 in the base portion 15 of the second blade 11 permits motion of the second blade 11 relative to the bolt 26 which interconnects the base portion 14 of the first blade 10, the first handle 16 and the second handle 18.

When the grips 29 are moved toward each other, the resilient portions 32 come into contact, limiting the inward travel and serving to cushion the shock transmitted to the operator.

During the cutting operation, the cutting edges 12,13 of the blades 10,11 are moved toward each other by the pivotal movement caused by moving the handles 16,18 together. First blade 10 pivots about the bolt 26. When an object to be severed is encountered by the cutting portions 12,13 of the blades 10,11, the stud 20 of the first blade 10 rides in the bearing surface of the slot 21 of the second blade and the second blade 11 is caused to pivot about the rivet 19, thereby effecting a compound severing action resulting in increased transverse contact pressure between the cutting surfaces 12,13 of the blades 10,11.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. Compound action shears comprising, first and second blade means disposed in parallel relationship, each of said blade means having a cutting portion and a base portion, stud means positioned in the base portion of the first blade means, elongated slot means positioned in the rear of the base portion of the second blade means so that the long axis of the slot means intersects the centerline of the second blade means at an angle of about 1 1 and adapted to receive the stud means of the first blade means, first handle means disposed adjacent the base portion of the first blade means, first fastening means fixedly interconnecting the first handle means and the first blade handle means respectively to limit relative travel of the handle means. 7

3. Compound action shears according to claim 2, in which the first and second stop means include resilient portions.

4. Compound action shears according to claim 1, in which the cutting portion of the second blade means is serrated.

5. Compound action shears according to claim 4, in which at least one of the blade means includes an arcuate cutting means. 

1. Compound action shears comprising, first and second blade means disposed in parallel relationship, each of said blade means having a cutting portion and a base portion, stud means positioned in the base portion of the first blade means, elongated slot means positioned in the rear of the base portion of the second blade means so that the long axis of the slot means intersects the centerline of the second blade means at an angle of about 11* and adapted to receive the stud means of the first blade means, first handle means disposed adjacent the base portion of the first blade means, first fastening means fixedly interconnecting the first handle means and the first blade means, second handle means disposed adjacent the base portion of the second blade means, second fastening means pivotally interconnecting the second handle means and the second blade means, bolt means interconnecting the first handle means, first blade means and the second handle means, elongated recess means located in the base portion of the second blade means forward of the elongated slot means to receive the bolt means.
 2. Compound action shears according to claim 1, including first and second stop means secured to the first and second handle means respectively to limit relative travel of the handle means.
 3. Compound action shears according to claim 2, in which the first and second stop means include resilient portions.
 4. Compound action shears according to claim 1, in which the cutting portion of the second blade means is serrated.
 5. Compound action shears according to claim 4, in which at least one of the blade means includes an arcuate cutting means. 